package com.hmdp.service.impl;

import cn.hutool.core.bean.BeanUtil;
import com.hmdp.dto.Result;
import com.hmdp.entity.VoucherOrder;
import com.hmdp.mapper.VoucherOrderMapper;
import com.hmdp.service.ISeckillVoucherService;
import com.hmdp.service.IVoucherOrderService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.utils.RedisIdWorker;
import com.hmdp.utils.UserHolder;
import lombok.extern.slf4j.Slf4j;
import org.redisson.api.RLock;
import org.redisson.api.RedissonClient;
import org.springframework.aop.framework.AopContext;
import org.springframework.core.io.ClassPathResource;
import org.springframework.data.redis.connection.stream.*;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.script.DefaultRedisScript;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import javax.annotation.PostConstruct;
import javax.annotation.Resource;
import java.time.Duration;
import java.util.Collections;
import java.util.List;
import java.util.Map;
import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

/**
 * <p>
 *  服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */

@Slf4j
@Service
public class VoucherOrderServiceImpl extends ServiceImpl<VoucherOrderMapper, VoucherOrder> implements IVoucherOrderService {

    @Resource
    private ISeckillVoucherService seckillVoucherService;

    @Resource
    private RedisIdWorker redisIdWorker;
    @Resource
    private StringRedisTemplate stringRedisTemplate;
    
    @Resource
    private RedissonClient redissonClient;
    private static final DefaultRedisScript<Long> SECKILL_SCRIPT;
    static {
        SECKILL_SCRIPT = new DefaultRedisScript<>();
        SECKILL_SCRIPT.setLocation(new ClassPathResource("seckill.lua"));
        SECKILL_SCRIPT.setResultType(Long.class);
    }

//    private BlockingQueue<VoucherOrder> orderTasks = new ArrayBlockingQueue<>(1024 * 1024);

    private static ExecutorService SECKILL_ORDER_EXECUTOR = Executors.newSingleThreadExecutor();

    @PostConstruct
    private void init() {
        SECKILL_ORDER_EXECUTOR.submit(new VoucherOrderHandler());
    }

    private class VoucherOrderHandler implements Runnable {

        @Override
        public void run() {
            while (true) {
                try {
                    // 1.获取消息队列中的订单信息 XREADGROUP GROUP g1 c1 COUNT 1 BLOCK 2000 STREAMS s1 >
                    List<MapRecord<String, Object, Object>> list = stringRedisTemplate.opsForStream().read(
                            Consumer.from("g1", "c1"),
                            StreamReadOptions.empty().count(1).block(Duration.ofSeconds(2)),
                            StreamOffset.create("stream.orders", ReadOffset.lastConsumed())
                    );
                    // 2.判断订单信息是否为空
                    if (list == null || list.isEmpty()) {
                        // 如果为null，说明没有消息，继续下一次循环
                        continue;
                    }
                    // 解析数据
                    MapRecord<String, Object, Object> record = list.get(0);
                    Map<Object, Object> value = record.getValue();
                    VoucherOrder voucherOrder = BeanUtil.fillBeanWithMap(value, new VoucherOrder(), true);
                    // 3.创建订单
                    createVoucherOrder(voucherOrder);
                    // 4.确认消息 XACK
                    stringRedisTemplate.opsForStream().acknowledge("s1", "g1", record.getId());
                } catch (Exception e) {
                    log.error("处理订单异常", e);
                    //处理异常消息
                    handlePendingList();
                }
            }
        }

        private void handlePendingList() {
            while (true) {
                try {
                    // 1.获取pending-list中的订单信息 XREADGROUP GROUP g1 c1 COUNT 1 BLOCK 2000 STREAMS s1 0
                    List<MapRecord<String, Object, Object>> list = stringRedisTemplate.opsForStream().read(
                            Consumer.from("g1", "c1"),
                            StreamReadOptions.empty().count(1),
                            StreamOffset.create("stream.orders", ReadOffset.from("0"))
                    );
                    // 2.判断订单信息是否为空
                    if (list == null || list.isEmpty()) {
                        // 如果为null，说明没有异常消息，结束循环
                        break;
                    }
                    // 解析数据
                    MapRecord<String, Object, Object> record = list.get(0);
                    Map<Object, Object> value = record.getValue();
                    VoucherOrder voucherOrder = BeanUtil.fillBeanWithMap(value, new VoucherOrder(), true);
                    // 3.创建订单
                    createVoucherOrder(voucherOrder);
                    // 4.确认消息 XACK
                    stringRedisTemplate.opsForStream().acknowledge("s1", "g1", record.getId());
                } catch (Exception e) {
                    log.error("处理pendding订单异常", e);
                    try{
                        Thread.sleep(20);
                    }catch(Exception e1){
                        e1.printStackTrace();
                    }
                }
            }
        }
    }
//    private class VoucherOrderHandler implements Runnable {
//
//        @Override
//        public void run() {
//            while(true) {
//                //1 获取队列中的订单信息
//                try {
//                    VoucherOrder voucherOrder = orderTasks.take();
//                    // 2 创建订单
//                    handlerVoucherOrder(voucherOrder);
//                } catch (Exception e) {
//                    log.error("处理订单异常", e);
//                }
//            }
//        }
//    }

    private void handlerVoucherOrder(VoucherOrder voucherOrder) {
        // 1 获取用户（不能在ThreadLocal中获取，因为这是其他线程）
        Long userId = voucherOrder.getUserId();
        // 2 获取锁
//        SimpleRedisLock lock = new SimpleRedisLock("order:" + userId, stringRedisTemplate);
        RLock lock = redissonClient.getLock("lock:order:" + userId);
        boolean isLock = lock.tryLock();
        // 3 判断是否获取锁成果
        if(!isLock) {
            log.error("不允许重复下单");
        }
        // 4 获取代理对象(事务)
        try {
            // 这里无法使用，因为AopContext.currentProxy也使用了ThreadLocal
//            IVoucherOrderService proxy = (IVoucherOrderService)AopContext.currentProxy();
            proxy.createVoucherOrder(voucherOrder);
        }finally {
            // 释放锁
            lock.unlock();
        }
    }

    // 成员对象，线程共享
    private IVoucherOrderService proxy;
    @Override
    public Result seckillVoucher(Long voucherId) {
        // 获取用户
        Long userId = UserHolder.getUser().getId();
        // 获取订单ID
        long orderId = redisIdWorker.nextId("order");
        //1 执行lua脚本
        Long result = stringRedisTemplate.execute(
                SECKILL_SCRIPT,
                Collections.emptyList(),
                voucherId.toString(),
                userId.toString(),
                String.valueOf(orderId)
        );
        //2 判断结果是否为0
        int r = result.intValue();
        if(r != 0) {
            //2.1 不为0，代表没有购买资格
            return Result.fail(r == 1 ? "库存不足" : "不能重复下单");
        }
        //3 获取代理对象
        proxy = (IVoucherOrderService)AopContext.currentProxy();
        //4 返回订单ID
        return Result.ok(0);

    }

//    @Override
//    public Result seckillVoucher(Long voucherId) {
//        // 获取用户
//        Long userId = UserHolder.getUser().getId();
//        //1 执行lua脚本
//        Long result = stringRedisTemplate.execute(
//                SECKILL_SCRIPT,
//                Collections.emptyList(),
//                voucherId.toString(),
//                userId.toString()
//        );
//        //2 判断结果是否为0
//        int r = result.intValue();
//        if(r != 0) {
//            //2.1 不为0，代表没有购买资格
//            return Result.fail(r == 1 ? "库存不足" : "不能重复下单");
//        }
//        //2.2 为0，有购买资格，把下单信息保存到阻塞队列
//        VoucherOrder voucherOrder = new VoucherOrder();
//        // TODO 保存阻塞队列
//        // 2.3 订单ID
//        long orderId = redisIdWorker.nextId("order");
//        voucherOrder.setId(orderId);
//        // 2.4 用户ID
//        Long userID = UserHolder.getUser().getId();
//        voucherOrder.setUserId(userID);
//        // 2.5 代金券ID
//        voucherOrder.setVoucherId(voucherId);
//        // 2.6 创建阻塞队列
//        orderTasks.add(voucherOrder);
//        //3 获取代理对象
//        proxy = (IVoucherOrderService)AopContext.currentProxy();
//        //4 返回订单ID
//        return Result.ok(0);
//
//    }
//    @Override
//    public Result seckillVoucher(Long voucherId) {
//        //1 查询优惠卷
//        SeckillVoucher voucher = seckillVoucherService.getById(voucherId);
//        //2 判断秒杀是否开始
//        if(voucher.getBeginTime().isAfter(LocalDateTime.now())) {
//            return Result.fail("秒杀尚未开始");
//        }
//        //3 判断秒杀是否已经结束
//        if(voucher.getEndTime().isBefore(LocalDateTime.now())) {
//            return Result.fail("秒杀已经结束");
//        }
//        //4 判断库存是否充足
//        if(voucher.getStock() < 1) {
//            return Result.fail("库存不足");
//        }
//        // 创建锁对象
//        Long userId = UserHolder.getUser().getId();
//        //获取锁
////        SimpleRedisLock lock = new SimpleRedisLock("order:" + userId, stringRedisTemplate);
//        RLock lock = redissonClient.getLock("lock:order:" + userId);
//        boolean isLock = lock.tryLock();
//        // 判断是否获取锁成果
//        if(!isLock) {
//            // 获取锁失败，返回错误或重试
//            return Result.fail("不允许重复下单!");
//        }
//        // 获取代理对象(事务)
//        try {
//            IVoucherOrderService proxy = (IVoucherOrderService)AopContext.currentProxy();
//            return proxy.createVoucherOrder(voucherId);
//        }finally {
//            lock.unlock();
//        }
//
//    }


    @Transactional
    public void createVoucherOrder(VoucherOrder voucherOrder) {

        //5 一人一单
        //5.1 查询订单
        Long userId = voucherOrder.getId();

        int count = query().eq("user_id", userId).eq("voucher_id", voucherOrder.getVoucherId()).count();
        //5.2 判断是否存在
        if (count > 0) {
            // 用户已经购买过了
            log.error("用户已经购买过了");
            return;
        }
        //6扣减库存
        boolean success = seckillVoucherService.update().setSql("stock = stock - 1") // set stock = stock - 1
                .eq("voucher_id", voucherOrder.getVoucherId()).
                gt("stock", 0).update();   // where id = ? and stock > 0
        if(!success) {
            log.error("库存不足");
            return;
        }
        // 7 创建订单
        save(voucherOrder);
    }

}
